The present invention relates to an improved construction of a modular rigid inflatable aquatic vessel, and, specifically, to such a structure that will greatly facilitate assembly and disassembly while retaining most, if not all, of the advantages of hitherto-proposed structures of this type. In addition, the structure of the invention will provide greater design flexibility in that the shape of the inflated shroud, tube or collar may be more varied and better economy of material because the stresses on the attachment means of the shroud, tube or collar to the rigid hull module may be more widely distributed by providing as described below.
A number of inflatable aquatic vessels have been proposed in this art and a number developed for use in naval, commercial and recreational applications. One construction, disclosed in my prior U.S. Pat. No. 4,498,413, the disclosure of which is incorporated herein by this reference, involves the use of an inflatable blader or a plurality of such bladders inside a shroud and arranged around and above the periphery of a rigid hull module. Such shroud may be attached removably to such rigid hull module by means of a boltrope, as disclosed in my co-pending application Ser. No. 618,147, filed June 7, 1984, the dislosure of which is incorporated herein by this reference, in which case the resulting aquatic vessel is modular. As such, the rigid hull portion is one module, the shroud is another module, and the bladder or bladders is or are another module or modules. The bladders may be attached and/or positioned by provision on or through the shroud, or on or through the rigid hull module. While the products made according to the aforereferenced disclosures of mine are advantaged, that is not to say improvement thereof is not possible.
Others have disclosed inflatable stuructures around and about the periphery of a rigid hull section, in which cases the complex-shaped structure or structures are air-containing vessels which, typically, are made of supported rubber or unsupported plastic film adhesively fastened to longitudinal straps which are adhesively or mechanially fastened to the rigid hull portion. Most mechanical fastenings, such as screws, bolts, rivets, eyes, grommets, lashings, lacings, concentrate stress between the rigid and flexible hull portions at points, increasing the probability of failure of the material and/or fastening at the points of attachment. The present invention is an advantageous way to attach continuously along lines such inflatable structures, as well as shrouds surrounding inflatable bladders, to a rigid hull portion; and the result is modular and readily assembled and disassembled for shipping, warehousing, nesting, storage, replacement of one or more modules, and/or repair of one or more modules.
In the case where a boltrope is used to attach the rigid hull module to the flexible portion, the rigid hull portion, usually at or near its periphery and at or just above the waterline, is provided with a C-sectioned channel which is open at at least one end to receive one end of the boltrope of the shroud module or inflatable member or members.
While such channel arrangement provides secure retention of the boltrope and the stresses between the rigid and inflatable portions of the boat are distributed along a line rather than concentrated at points, the complex shape of the flexible portion causes difficulty when the boltrope of the flexible portion is "threaded" into and along most or all of the length of the mating channel. The sharper the bends, or the more acute the angles, on the periphery, the greater the difficulty. Also, as the channels become dirty, corroded, the host for marine growth, and damaged, the threading task becomes more difficult.
It is, therefore, an object of the present invention to provide for a structure for a rigid inflatable vessel for which assembly and disassembly will be vastly facilitated for all categories of users and/or of which the shape will be vastly less limited by the shapes of the flexible-portions and their attachment means. Moreover, this invention will provide a construction which retains or provides line loading of the stresses between the rigid and flexible hull portions and distributes such stresses over a larger area of the rigid hull portion.
According to the principles of this invention, the rigid hull module, usually at or near its periphery and at or just above the waterline, is provided with a C-section peripheral channel for receiving the outer of two boltropes along most or all of the length of the flexible hull portion. Such peripheral channel extends most or all the way around the vessel, transoms in the cases of power boats being a notable and obvious exception wherebeyond the flexible portion typically extends equally on both sides of the boat but wherealong the flexible postion does not continue. Such flexible portion has a second, inner boltrope, generally parallel to and the same length as said outer boltrope. While said inner and outer boltropes may be either the same size and materials or different sizes and made of different materials, or positions on the same or different horizontal plane or planes, it is often to make them alike. A plurality of discrete C-section inner channel members are provided which, after threading the desired number of them in the desired sequence onto and essentially all along said inner boltrope, are each removably attached to the rigid hull module generally before inflation and along a line inside of, parallel to, and most or all of the distance along the said peripheral channel. Each inner channel member may be either attached to the rigid hull module at a single point or multiple points on that member, or on a line along some or all its length. Removeable attachment of each inner channel member to the rigid hull module may be by screw of screws, bolt or bolts, hook or hooks, eye or eyes, rope tie or ties, rope lashing or lashings, shock cord tie or ties, shock cord lashing or lashings, or other suitable means. Said inner channel members may be some or all of the same or different lengths, straight or curved, and attached to the rigid hull portion by the same or different means; design features which may be varied to suit a particular vessel requirement. In cases where bladders are used, typically the bladders are affixed to the shroud module or rigid hull module before the inner channel members are removably attached to the rigid hull module; but not necessarily, because an advantage of this present invention is that one or some inner channel members may be dis-attached in order to gain access to a nearby wholly or partially deflated bladder or bladders without deflating all the bladders or disassembling the entire modular vessel. In addition to dividing the stresses between the rigid and flexible hull portions over two boltropes and a larger area of the rigid hull module, two boltropes and their mating C-section channels can afford a space therebetween wherein manifold pipes or tubes for the purpose of inflating and/or deflating the bladders can reside the the protection of the shroud module and/or the rigid hull module. After said inner channel members are threaded onto the inner boltrope, they may be flexibly or rigidly attached to each other at their ends, merely snugged together, or gaps may remain between them; and their ends may or may not have mating means. The result is a segmented channel line for holding the inner boltrope in the desired position. From the description that follows, it will be apparent to those skilled in this art that separate and generally parallel boltropes can provide better control over the position of the flexible hull portion relative to the rigid hull portion than attachment at points of continuously along a line, and more useful sole area can be a result. It can be advantageous to use adhesive bonding in place of the peripheral boltrope and mating C-section channel along with the inner boltrope and channel members disclosed hereinabove.